Move kernel baseline tests to front_end.

pkg/front_end/testcases/rasta/bad_explicit_super_constructor.dart

 // Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE.md file.
 
 class A {
   A(x);
 }
 
 class B extends A {
   const B() : super();
 }
 
 main() {
   new B();
   const B();
 }